As we noted back in September, existing trans-Pacific cables generally provide on average 3.3 tbps of capacity. But bandwidth is getting tight and carriers have recently been scrambling to upgrade these cables or, in some cases, build entirely new ones (like Verizon).

According to research firm TeleGeography, trans-Pacific internet traffic shot up 41 percent between mid-2006 and mid-2007. But as the only non-telecom company in the new consortium, don’t expect Google’s involvement to signal a new trend, analysts warn.

"Although many non-telecom companies have high bandwidth requirements, few will venture into owning submarine cables anytime soon," said TeleGeography’s research director Alan Mauldin in a Monday research note.

That likely has a lot to do with cost. As it stands, the Unity cable will cost $300 million to build and the task will be split between Tyco Telecommunications and NEC.

Add to that the fact that the sub-sea cable business isn’t the most stable or lucrative, and Google’s involvement seems more of an attempt simply to bring down the cost of moving massive amounts of traffic around the world.

“You add markets with new supply, and the price is bound to come down,” Eric Schoonover, a senior analyst at TeleGeography told Wired last fall. “There’s even a risk of it collapsing,” he says, as it did in 2000.

Nevertheless, Google’s investment in the Unity cable seems to be in line with the company’s approach to buying (and lighting) dark fiber here in the U.S., experts say, and will now give it the chance to acquire even more capacity at cost.

Unity is initially expected to increase trans–Pacific lit cable capacity by about 20 percent, according to Telegeography, with the potential to add up to 7.68 tbps of bandwidth across the Pacific.

Google says the 6214 mile cable will provide connectivity between the Tokyo coast and Los Angeles, as well as other West Coast network points — unless an anchor falls on it. Construction will begin immediately.

The one thing no one discussed on Monday was how much Google (or any other consortium member) is actually chipping in for Unity. Based on previous conversations with analysts, your bandwidth seems to be proportionate to the amount to money you plug into the consortium for buildout and other infrastructure costs. If everyone’s forking over $50,000,000, that’s one thing. But if Google feels it wants (or needs) a little extra bandwidth, the company could end up fronting quite a bit more than 50 mil. Google did not immediately respond to our request for comment.